With a 2-sided Bakugan I can easily get it to land on the same side repeatedly in RL. :- So bad rule IMO.
Yeah, you just need to spin it with the correct magnet touching the table. It will most always land on the side you want it to. But I think for Bakugan with wheels (like Elico, Preyas and Elfin) the people who use them should actually set them down on a card when they want to roll them to determine the attribute/g power.